Note 7 - Loans (Details) - Allowance for Loan Losses by Portfolio Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for possible credit losses	$ 617	$ (37)
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	65,103	66,101
Provision for possible credit losses	4,888	(3,310)
Charge-offs	(7,226)	(2,690)
Recoveries	2,017	955
Net charge-offs	(5,209)	(1,735)
Ending Balance	64,782	61,056
Reserve for impaired loans	4,663	1,717
Reserve for non-impaired loans	60,119	59,339
Reserve for off-balance sheet credit commitments	929	837
Real Estate Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	11,999	23,017
Provision for possible credit losses	(1,398)	(2,399)
Recoveries	25	79
Net charge-offs	25	79
Ending Balance	10,626	20,697
Reserve for impaired loans	3,129	8,080
Reserve for non-impaired loans	7,497	12,617
Reserve for off-balance sheet credit commitments	326	311
Commercial Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	84,753	82,473
Provision for possible credit losses	(4,306)	2,968
Charge-offs	(1,698)	(990)
Recoveries	2,577	365
Net charge-offs	879	(625)
Ending Balance	81,326	84,816
Reserve for impaired loans	6,165	6,242
Reserve for non-impaired loans	75,161	78,574
Reserve for off-balance sheet credit commitments	445	2,122
Residential Mortgage And Equity Lines Member
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	12,005	11,703
Provision for possible credit losses	447	795
Charge-offs	(78)	(410)
Recoveries	3	3
Net charge-offs	(75)	(407)
Ending Balance	12,377	12,091
Reserve for impaired loans	538	1,318
Reserve for non-impaired loans	11,839	10,773
Reserve for off-balance sheet credit commitments	33	33
Installment And Other Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	29	28
Provision for possible credit losses	(2)	4
Ending Balance	27	32
Reserve for impaired loans		0
Reserve for non-impaired loans	27	32
Reserve for off-balance sheet credit commitments	1	2
Total [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	173,889	183,322
Provision for possible credit losses	(371)	(1,942)
Charge-offs	(9,002)	(4,090)
Recoveries	4,622	1,402
Net charge-offs	(4,380)	(2,688)
Ending Balance	169,138	178,692
Reserve for impaired loans	14,495	17,357
Reserve for non-impaired loans	154,643	161,335
Reserve for off-balance sheet credit commitments	$ 1,734	$ 3,305